Abstract
The action of aldosterone to increase apical membrane permeability in responsive epithelia is thought to be due to activation of sodium channels. Aldosterone stimulates methylation of a 95-kDa protein in apical membrane of A6 cells, and we have previously shown that methylation of a 95-kDa protein in the immunopurified Na+ channel complex increases open probability of these channels in planar lipid bilayers. We report here that aldosterone stimulates carboxylmethylation of the β subunit of xENaC in A6 cells. In vitro translated β subunit, but not α or γ, serves as a substrate for carboxylmethylation. Carboxylmethylation of ENaC reconstituted in planar lipid bilayers leads to an increase in open probability only when β subunit is present. When the channel complex is immunoprecipitated from A6 cells and analyzed by Western blot with antibodies to the three subunits of xENaC, all three subunits are recognized as constituents of the complex. The results suggest that Na+ channel activity in A6 cells is regulated, in part, by carboxylmethylation of the β subunit of xENaC.
| Original language | English |
|---|---|
| Pages (from-to) | 28746-28751 |
| Number of pages | 6 |
| Journal | Journal of Biological Chemistry |
| Volume | 273 |
| Issue number | 44 |
| DOIs | |
| Publication status | Published - Oct 30 1998 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Carboxylmethylation of the β subunit of xENaC regulates channel activity. / Rokaw, Michael D.; Wang, Jun M.; Edinger, Robert S.; Weisz, Ora A.; Hui, Daniel; Middleton, Pamela; Shlyonsky, Vadim; Berdiev, Bakhrom K.; Ismailov, Iskander; Eaton, Douglas C.; Benos, Dale J.; Johnson, John P.
In: Journal of Biological Chemistry, Vol. 273, No. 44, 30.10.1998, p. 28746-28751.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Carboxylmethylation of the β subunit of xENaC regulates channel activity
AU - Rokaw, Michael D.
AU - Wang, Jun M.
AU - Edinger, Robert S.
AU - Weisz, Ora A.
AU - Hui, Daniel
AU - Middleton, Pamela
AU - Shlyonsky, Vadim
AU - Berdiev, Bakhrom K.
AU - Ismailov, Iskander
AU - Eaton, Douglas C.
AU - Benos, Dale J.
AU - Johnson, John P.
PY - 1998/10/30
Y1 - 1998/10/30
N2 - The action of aldosterone to increase apical membrane permeability in responsive epithelia is thought to be due to activation of sodium channels. Aldosterone stimulates methylation of a 95-kDa protein in apical membrane of A6 cells, and we have previously shown that methylation of a 95-kDa protein in the immunopurified Na+ channel complex increases open probability of these channels in planar lipid bilayers. We report here that aldosterone stimulates carboxylmethylation of the β subunit of xENaC in A6 cells. In vitro translated β subunit, but not α or γ, serves as a substrate for carboxylmethylation. Carboxylmethylation of ENaC reconstituted in planar lipid bilayers leads to an increase in open probability only when β subunit is present. When the channel complex is immunoprecipitated from A6 cells and analyzed by Western blot with antibodies to the three subunits of xENaC, all three subunits are recognized as constituents of the complex. The results suggest that Na+ channel activity in A6 cells is regulated, in part, by carboxylmethylation of the β subunit of xENaC.
AB - The action of aldosterone to increase apical membrane permeability in responsive epithelia is thought to be due to activation of sodium channels. Aldosterone stimulates methylation of a 95-kDa protein in apical membrane of A6 cells, and we have previously shown that methylation of a 95-kDa protein in the immunopurified Na+ channel complex increases open probability of these channels in planar lipid bilayers. We report here that aldosterone stimulates carboxylmethylation of the β subunit of xENaC in A6 cells. In vitro translated β subunit, but not α or γ, serves as a substrate for carboxylmethylation. Carboxylmethylation of ENaC reconstituted in planar lipid bilayers leads to an increase in open probability only when β subunit is present. When the channel complex is immunoprecipitated from A6 cells and analyzed by Western blot with antibodies to the three subunits of xENaC, all three subunits are recognized as constituents of the complex. The results suggest that Na+ channel activity in A6 cells is regulated, in part, by carboxylmethylation of the β subunit of xENaC.
UR - http://www.scopus.com/inward/record.url?scp=15444343017&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=15444343017&partnerID=8YFLogxK
U2 - 10.1074/jbc.273.44.28746
DO - 10.1074/jbc.273.44.28746
M3 - Article
C2 - 9786871
AN - SCOPUS:15444343017
VL - 273
SP - 28746
EP - 28751
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 44
ER -